This invention relates to a form-fill-seal type packaging machine for continuously producing packaged products by filling bags with articles such as candies while these bags are being formed.
As disclosed for example in Japanese Patent Publication Tokkai 10-7102, a packaging machine of this type is typically adapted to bend an elongated bag-making material (the "film") by wrapping it around a tubular chute, to make it into a tubular form by sealing its side edges together longitudinally, to thereafter seal it and cut it transversely at specified intervals to continuously form bags, and to drop articles to be packaged into the bags through the chute while these bags are being formed. The transverse sealing of the tubularly formed film is usually carried out by clamping it by a device for thermal sealing, and the film is separated at the sealed positions to be made into individual packaged bags. Thus, the sealing must be effected during time intervals between periods during which articles are dropped through the chute.
The current tendency in the packaging technology is to shorten the intervals at which the articles to be packaged are dropped in successive batches so as to improve the productivity. Although the intervals are shortened, there will be enough space of time left between the dropping of one batch to that of the next if articles in each batch drop closely together and the sealing device can be operated to clamp the film during such a space of time. In reality, however, articles which are dropped together as a batch become dispersed while undergoing a free fall inside the chute. As a result, it is likely that some of the articles are caught when the sealing device clamps the film transversely.